Perhaps you’re one of those people who get their dander up when you hear creationists saying “I’m not descended from some monkey” not only for the obvious reason, but also because you can’t help but blurt out, “No, you mean ‘ape!’ We’re apes, not monkeys.”
Indeed, our superfamily, Hominoidea, split from the group labeled “old world monkeys” millions of years ago—but perhaps not as many million as we thought. In Nature this week, a team of scientists report on a 28-29 million year old fossil that appears to predate the split, meaning the separation would have happened more recently than other studies suggested.
The partial skull of this new creature, which the team dubbed Saadanius hijazensis, turned up in Saudi Arabia in February 2009.
Do chimpanzees truly understand the concept of death–and do they grieve for their dead? Two separate studies due to be published in journal Current Biology suggest that chimps may have emotional responses to death that aren’t so different from humans’ reactions.
In the first study, researchers observed an ailing female chimp in a Scottish zoo. The elderly chimp, called Pansy, was believed to be more than 50 years old. As Pansy’s health began to falter, other chimps, including Pansy’s daughter, began to exhibit signs of concern that seemed remarkably human. They groomed Pansy more often than usual as she became lethargic, and after her death, her daughter stayed near the body for an entire night, even though she had never slept on that platform before. All of the group were subdued for several days afterwards, and avoided the place where she had died, spending long hours grooming each other [BBC].
In the second study, scientists working in the forests of Guinea observed two chimp mothers carrying around the bodies of their dead infants for weeks after their deaths. One chimp carried her dead baby around for more than 60 days, an unusually long period, according to the scientists. During the period, the babies’ bodies slowly mummified as they dried out. The bereaved mothers used tools to fend off flies [BBC].
For an in-depth examination of what these two studies reveal about our closest ancestor’s understanding of death and mortality, read Ed Yong’s post in the DISCOVER blog “Not Exactly Rocket Science.”
DISCOVER: Chimps Show Altruistic Streak
DISCOVER: The Discover Interview: Jane Goodall
DISCOVER: Chimps Plan Ahead. (Plan #1: Throw Rocks at Humans.)
80beats: Chimps Don’t Run From Fire—They Dance With It
80beats: Chimps Catch Contagious Yawns From Cartoons
80beats: Scientists Tickle Apes & Conclude Laughter Is at Least 10 Million Years Old
Last week’s meeting of the Convention on International Trade in Endangered Species (CITES) put the spotlight on marine species like the bluefin tuna and some endangered sharks, as the meeting failed to protect them from being overfished to extinction. But a new survey published in the UK journal Mammal Review reminds us that it’s not just marine animals that are endangered by humans, but also primates.
The survey showed that despite CITES’ tight trade regulations for primates, more than a hundred primate species, from gorillas to monkeys to tiny lorises, are endangered by traditional medicine. The survey found that animals across the world were being hunted and killed for their perceived magical or medicinal values–of the 390 species studied, 101, or more than a quarter, are regularly killed for their body parts, with 47 species being used for their supposed medicinal properties, 34 for use in magical or religious practices, and 20 for both purposes [BBC].
The survey found that people still use primate parts to treat a wide variety of ailments. In Bolivia, spider monkey parts are used to cure snake bites, spider bites, fever, coughs, colds, shoulder pain, and sleeping problems; in India, the survey found that many people believe that macaque blood is a cure for asthma. Other monkeys or lorises have their bones or skulls ground up into powder administered with tea, or have their gall bladders ingested or blood or fat used as ointments [BBC]. Monkeys are also valued in Sierra Leone, where a small piece of chimpanzee bone is tied to a child’s waist or wrist, as parents believe it will make the child stronger as he grows older.
When it comes to understanding fire, chimpanzees might have a leg up not only on the rest of the animal kingdom, but also on those of us in the human species who would sprint in the other direction at the sight of a blaze. A study published in the American Journal of Physical Anthropology argues that these primates don’t panic when the flames start, and could even understand the basics about how fire behaves.
Primatologist Jill Pruetz has been observing chimps in Senegal since 2001, but it was in 2006 that she first noticed how the animals reacted to wildfire. When people in the area set fires to clear the land, the chimps refused to tuck tail and run. “It was the end of the dry season, so the fires burn so hot and burn up trees really fast, and they were so calm about it,” Pruetz said of the chimps. “They were a lot better than I was, that’s for sure” [LiveScience].
Yawning is so contagious that even chimpanzees who watched animations of cartoon chimps yawning couldn’t resist the impulse, according to a new study in Proceedings of the Royal Society B. Study coauthor Matthew Campbell doesn’t think the chimps were “fooled” by the animations into thinking they were looking at real chimps, he explained that there was evidence that chimpanzees “process animated faces the same way they process photographs of faces”. He said: “It’s not a real chimpanzee, but it kind of looks like a chimpanzee, and they’re responding to that” [BBC News].
The chimps were tested by first showing them animated chimps making a variety of facial expressions, and then another set of cartoons with yawning chimps. Only the latter cartoons elicited the yawning response. Campbell says the findings could assist in the future study of empathy…. “We’re interested in using animation for presenting stimuli to animals, because we can control all the features of what we show them” [BBC News].
As for why yawns are so contagious, Campbell suggests that the phenomenon may have evolved to allow some animals “to coordinate activity better, resting when other individuals are resting” in order that they “can travel when it’s time to travel, eat when it’s time to eat” [Discovery News].
80beats: Scientists Tickle Apes & Conclude Laughter Is at Least 10 Million Years Old
80beats: Male Chimpanzees Share Meat in Return for Sex
80beats: Chimp Gathers Stones for “Premeditated” Attacks on Zoo Visitors
Image: J. Devyn Carter. Still frames from the animated yawning.
Using the first known animal instruments, orangutans use leaves to make their voices sound deeper, perhaps thereby tricking predators into thinking the apes are bigger than they really are, according to a study published in the journal Proceedings of the Royal Society B.
Orangutans produce a noise known as “kiss squeaks” to let predators like snakes and leopards know that they’ve been spotted, and can use their lips and fingers or folded leaves to make the sound. To find out more about why the animals produce the noise, researchers recorded kiss squeaks between 2003 and 2005 near a research station … on the island of Borneo. The team noted whether the sounds had been made with hands, leaves, or lips alone [National Geographic News]. They found that squeaks made using only the lips had a higher pitch than those produced using hands, and that leaf-produced pitches had the lowest frequency and therefore the deepest sound.
Researchers have determined how malaria first came to afflict humanity, and have laid the blame on our closest relative, the chimpanzee. Researchers have long known that chimps get infected with a malaria parasite of their own, called Plasmodium reichenowi, which is closely related to the human malaria parasite, Plasmodium falciparum, but they believed that the two parasites evolved from a common ancestor many millions of years ago and then developed on parallel tracks. Now a new genetic comparison indicates that the human version more likely developed from the chimpanzee type [AP].
“Current wisdom that P. falciparum has been in humans for millions and millions of years is wrong,” said study co-author Nathan Wolfe, director of the Global Viral Forecasting Initiative…. “We now know that there was a point in time when this was primarily a disease in chimpanzees that jumped and took hold in humans” [National Geographic News]. Malaria probably came to our species when mosquitoes that had previously fed on infected chimpanzees bit humans, Wolfe says, and the transmission may have happened as recently as 10,000 years ago.
In the first known case of its kind, scientists have identified a strain of HIV that can be traced to gorillas, not chimpanzees, according to a report in Nature Medicine. The new strain was detected in a Cameroonian woman living in France.
Previous strains of HIV virus type 1, the main type of the disease, have been shown to have arisen from chimpanzees, and researchers found that the new virus is dissimilar enough from previously known strains that it cannot be detected by standard HIV tests. After genetic analysis, scientists also found that the infection is closely related to gorilla simian immunodeficincy virus, or SIVgor, the gorilla version of HIV. Genetic analysis of the woman’s virus shows that it is so closely related to SIVgor that “the most likely explanation for its emergence is gorilla-to-human transmission” [Bloomberg], says co-author Jean-Christopher Plantier.
It may seem as though orangutans’ 180-pound bodies would be unwieldy when it comes to swinging from delicate tree branches in the rainforests of Indonesia and Malaysia. But the animals have figured out a variety of ways to navigate treetops, allowing them to avoid a potentially deadly fall, according to a study published in the Proceedings of the National Academy of Sciences.
When scientists observed wild orangutans in the Sumatran rainforest, they found that the animals traversed the delicate branches by moving their bodies with a rhythm that counters the vibrations of the trees. At the highest treetops in the forest, tree branches are thin and begin to wobble as animals climb on them, much as a suspension footbridge vibrates as people walk over it. Too much vibration and an orangutan can be thrown off altogether. From high in the trees, such a fall would be deadly [Time]. But because orangutans move with an irregular beat, they avoid compounding the already-shaking branches with the motion of their own bodies. Also increasing their stability, the animals also have the habit of grasping more than one branch at once–in fact, nearly one-third of the time, orangutans held on to more than four branches simultaneously.
Scientists have long known that chimpanzees and other nonhuman primates can become infected with simian immunodeficiency virus, or SIV, a variant of HIV. It was thought, however, that only Asian macaque monkeys could die from the infection. But a new study published in Nature contradicts this assumption by finding that the virus can also be deadly to chimpanzees, humans’ closest relatives.
Some wild primates appear to have developed a way to keep SIV from becoming deadly, and scientists had hoped that studying chimpanzees could reveal how this mechanism works, possibly opening to the door to a human remedy. The new results suggest that it will not be possible to find the key to HIV immunity in the chimpanzee genome, as scientists had hoped. However, the study… sets the stage for researchers to gain insight into how HIV and SIV cause disease in their hosts by studying the responses of different primates to the viruses [Nature News].